Jon Snow (played by Kit Harington on the HBO adaptation) is known Westeros-wide as Ned Stark’s bastard son, but a popular “Game of Thrones” fan theory could change everything for the Watcher on the Wall.

WARNING! WARNING! SPOILERS AHEAD!

In a new video detailing a theory that’s been discussed amongst die-hard fans of George R. R. Martin’s “A Song of Ice and Fire” series, Youtube user Alt Shift X lays out the very convincing evidence that seems to solve the mystery, with an answer that should be quite shocking to fans who maybe haven’t been following quite as closely as the fan-sleuths.

Needless to say, possible spoilers will follow if this theory does indeed turn out to be true.

According to Alt Shift X and a faction of the “Game of Thrones” fanbase, Martin has laid out throughout the first five books in his series that Jon Snow is actually not Ned Stark’s bastard son at all, but the son of Ned’s sister Lyanna Stark, and her lover, Rhaegar Targaryen, the late older brother to Daenerys Targaryen, played by Emilia Clarke on the show.

The evidence laid out in the video is extensive, maybe even undeniable, and the implications of such a revelation would certainly change things for the many lords and armies clamoring to claim the Iron Throne, but as of Martin’s fifth book in the series, “A Dance with Dragons,” it has not been confirmed, much less revealed to any of the characters.

So it may be a while yet until we discover if this theory holds any water, especially since Ned Stark is dead. HBO has already renewed the show for at least two more seasons, with shooting on season 5 set to take place at least partly in Spain starting this month.